Shot shell process



Feb. 20, 19% J. W, S ANSEY "3,369,443

SHOT SHELL PROCESS Filed Oct. 4, 1966 I NVENTORS' JOHN 144 SHANSEV FIG-7limited States Patent ()fiice 3,369,443 Patented Feb. 20, 1968 3,369,443SHOT SHELL PROCESS John W. Shansey, Alton, 111., assignor to OlinMathieson Chemical Corporation, a corporation of Virginia Filed Oct. 4,196,6, Ser. No. 584,191 3 Claims. (Cl. 86-10) ABSTRACT OF THE DISCLOSUREA method of combining a one-piece plastic shot shell case having aflange with a metallic cup having a rim, while insuring that the flangeis fully received within the rim and the case is fully seated.

The present invention relates to ammunition casings and relates inparticular to a one-piece plastic shot shell case and a method ofcombining such a case with a metallic cup.

More particularly, the invention deals with a novel process forcombining a one-piece plastic shot shell casing formed at one end with aradially projecting flange with its complementary metallic cup having aradially projecting hollow rim for receiving the flange.

A particular feature of the invention is the provision of a novelprocess for ensuring that the radially projecting flange of the plasticshot shell casing enters and is fully received throughout 360 by itsmating hollow rim formed in the metallic cup and that the base of thecase makes areal contact with the bottom of the cup.

A representative embodiment of the present invention may comprise thesteps of reforming the flange from its radially projecting or firstposition to a second position defining a circular skirt depending fromthe tubular casing so that the skirt and the tubular casing aregenerally coaxial, inserting the casing so reformed into a metallic cupuntil the casing bottoms in the cup, said circular skirt by virtue ofits natural tendency to return to its first position tending to feedinto or enter said hollow rim as the casing bottoms, and thereafterforcing or working the casing relative to the cup to ensure that thehollow rim is filled throughout its circumference by said flange, and

the base of the case in in areal contact with the bottom of the cup.

Other features and advantages of the present invention will become moreapparent from an examination of the succeeding specification whenconsidered in conjunction with the appended drawings, in which:

FIG. 1 is a vertical section of a loaded shot shell where the plasticcasing and the metallic cup have been combined in accordance with theprinciples of the invention;

FIG. 2 is a vertical section of the head or base portion of a plasticshot shell before combination with a metallic p;

FIG. 3 is a similar section of a metallic cup with which the baseportion of FIG. 2 is combined;

FIG. 4 shows tooling for reforming the flange from the radial positionto the depending position;

FIG. 5 shows the step following the representation of FIG. 4;

FIG. 6 is an enlarged view of a portion of FIG. 5 showing therelationship of the flange and rim at the instant of bottoming; and

FIG. 7 is an enlarged view of FIG. 1 showing the finished assembly afterthe final working or forcing step with the flat faces of the flange andthe boss in a coplanar position.

Referring now in detail to the drawings, note that FIG. 1 shows aplastic shot shell case identified as P in combination with a metalliccup M where one end of the case P includes a radially projecting flangeF mating with a corresponding hollow rim R.

As stated previously, the present invention is directed to a novelprocess for more efficiently affecting the combination of the shot shellcasing with a metallic cup to ensure that the casing flange interlocksor mates with the hollow rim throughout their respective peripheries andthat the bottom of the case makes areal contact with the cup.

FIG. 2 shows the head 10 of a plastic shot shell including a radiallyprojecting flange 11 having a flat annular face 12 surrounding andoffset from a boss 13 also having a flat face.

Aperture 14 is provided for receiving a primer assembly such as isrepresented in FIG. 1 by the letter A. FIG. 3 shows a metallic cup 16having a hollow rim 17; the dimensions of the cup 16 including itshollow rim 17 are selected to complement the casing 10 and its flange11.

FIG. 4 shows the casing 10 entering a forming die 18 whose tapered sidewall 19 is operative as the casing is advanced in the direction of thearrow by mandrel 21 to reform flange 11 from its radial condition ofFIG. 2 into a circular depending skirt identified in FIG. 4 by thereference numeral 22.

FIG. 5 illustrates the relative position of the metallic cup 16 and thecasing 10 at the instant of bottoming.

In this figure, it is apparent that female die 23 serves as a seat formetallic cup 16 as well as for primer 24 shown in position in primeraperture 14.

Referring now to FIG. 6, which is an enlarged view of a portion of FIG.5, note that the flat face 26 of boss 13 is in face-to-face contact withthe mating surface of the cup 16.

Note further that the flange 11, while having returned to its generallyradial position, has not fully entered the hollow rim 17 of the metalliccup 16.

Furthermore, note that the face 12 of the flange 11 is not fully incontact with the flat face of the metallic cup 16 nor are the faces ofthe boss and the flange coplanar.

Upon the application of additional pressure by the tooling of FIG. 5,the rim 17 of the cup is crimped and the plastic case is forced orworked so that the assembled elements assume the condition shown inFIG. 1. (See FIG. 7, an enlargement of a portion of FIG. 1).

Referring in particular to FIG. 7, note that upon completion of thefinal step, the flange 11 fully enters and entirely occupies the hollowrim 17. In addition, the flat faces 12 and 26 of the flange 11 and theboss 13, respectively, are coplanar but are intercepted by an annularundercut or groove defined by the reference numeral 27.

The particular advantage of the present invention is to develop auniform hoop stress encircling and compressing primer A while insuringthat the base of the plastic case is snugly in areal contact with thebottom of the metal cup.

In prior art arrangements and without the process steps of the presentinvention, the flange 11 does not enter the hollow rim fully throughout360 and frequently there is a gap or space between the base of the caseand the cup. When the flange 11 is not fully seated or when the flange11 buckles or otherwise refuses to enter and fill out the mating portionof the hollow rimthroughout 360", the primer opening 14 is deformed ordistorted making it difficult to insert and retain the primer.

Correspondingly, if the case is not fully in areal contact with thebottom of the cup, the primer tends to float relative to the casecausing firing difliculties.

Stated otherwise, the process steps of the present invention develop inthe side walls of the primer opening 14 a uniform compressive resistancein a radial direction outwardly from the primer opening, therebyavoiding distortion in the opening and developing uniform peripheralsqueeze on the primer after assembly. The primer has a firm seatassuring reliable detonation.

It is anticipated that a variety of embodiments of the present inventionmay be devised without departing from the spirit and scope thereof.

What is claimed is:

1. A method of combining a one-piece plastic shot shell casing having aradially projecting flange surrounding an offset boss at one end of thecasing with a metallic cup having a complementary radially projectinghollow rim comprising the steps of: reforming said radially projectingflange to define a circular skirt depending from the tubular body sothat the skirt is generally coaxial with the tubular body, insertingsaid casing with the reformed flange into said metallic cup until theoflset boss bottoms in the cup, said depending skirt by virtue of itsnatural tendency to return to its condition defining a radiallyprojecting flange tending to feed into said hollow rim as the offsetboss bottoms in the cup, and after bottoming said olfset boss workingsaid plastic casing particularly said offset boss relative to said cupto drive said flange radially into the hollow rim to ensure that saidhollow rim is completely filled throughout its circumference by saidflange and that said casing is in areal contact with the bottom of saidcup, the plastic material fo said offset boss providing during saidworking step a body of plastic material useful to drive said flangeoutwardly in a radial direction.

2. The method of claim 1, wherein the working step after bottomingeliminates the offset condition of the boss and renders the face of theflange and the boss coplanar.

3. A method of combining a one-piece plastic shot shell casing with ametallic cup having a radially projecting hollow rim comprising thesteps of: forming a one-piece plastic shot shell casing with a tubularbody and with a circular, radially projecting flange at one end of thetubular body, turning said flange downwardly through an arc of about 90so that the flange forms a circular skirt depending from the tubularbody, inserting said one-piece casing with said circular skirt into themetallic cup until the casing bottoms in the cup, said flange by virtueof its natural tendency to return to its radially projecting positionbeing operative to feed into said hollow rim as the casing bottoms inthe cup effective to ensure that said hollow rim is completely filledthroughout its circumference by said flange.

References Cited UNITED STATES PATENTS 977,497 12/1910 Bailey 86-123,242,789 3/1966 Woodring 86-1l BENJAMIN A. BORCHELT, Primary Examiner.

P. A. SHANLEY, G. H. GLANZMAN,

Assistant Examiners.

